Many home heating systems use oil as their fuel. In the typical situation, the oil furnace and its associated oil tank are located in the basement of the house, with heat being delivered to the upstairs living spaces by hot water circulated through radiators or hot air discharged through vents.
The oil tanks typically have a refill line which extends from the oil tank up to the side of the house, where the refill line can be accessed for refilling by an oil truck. In addition, the oil tanks typically have a fuel level gauge, commonly called a sight glass, on the top of the tank to show how much oil is in the oil tank.
More particularly, and referring now to FIGS. 1–3, there is shown a conventional oil tank sight glass SG. Sight glass SG is transparent and contains a moving indicator MI which is supported by a shaft S which is in turn attached to a float (not shown) located in the oil tank (not shown). The height of moving indicator MI within sight glass SG corresponds to the height of the oil in the oil tank: as the level of the oil in the oil tank decreases, the height of moving indicator MI drops within sight glass SG.
The foregoing arrangement provides a simple, reliable and economical means for indicating the amount of oil present in the oil tank. Unfortunately, however, this arrangement also suffers from the fact that it is limited to line of sight. Thus, where the oil tank is located in the basement of a house, a person must go down to the basement in order to check on the level of oil in the oil tank. This can be inconvenient and may lead to a failure to regularly monitor the level of oil in the oil tank, which may in turn result in accidentally depleting all of the oil in the oil tank.